One of the major problems child specialists face daily is the school-age hyperactive child. Research on hyperactivity suffers from many glaring methodological errors. Favorable drug effects are reported when professional opinion or rating scales are used, but not when measures of behavior are used. Well-controlled studies in laboratory environments are not applicable to the natural environment. Clearly, a technology to measure hyperactive behavior in its natural environment is needed. The goal of the first year of this three-year research project will be to develop two objective measures of hyperactivity: (a) motor behavior, and (b) social behavior. A video tape technology will be developed to measure hyperactivity in the classroom and in the home. The project will be aimed primarily at the training of a staff to analyze motion and social interaction from the video tapes, the development of equipment systems to rapidly and efficiently code data from the video tapes, and to obtain a general and systematic analysis of what constitutes hyperactivity in the child's natural environment. The second and third years will be aimed at evaluating the most effective treatment techniques: (a) either Ritalin (methylphenidate) or Mellaril (thioridazine) or (b) behavior modification. The result of this research should be: (a) the development of a naturalistic measurement technology for studying the hyperactive child; and (b) an improved assessment of the relative value of drug and behavior modification treatment considering the characteristics of the hyperactive child.